Modal analysis of ultra-compact channel filters based on race-track photonic crystal ring resonators

Abstract

A new channel drop filter (CDF) is proposed based on a race-track photonic crystal ring resonator composed of square-lattice cylindrical silicon rods in air. By using a two-dimensional finite-difference, time-domain numerical technique, the modal behavior of two representative CDFs, parallel and perpendicular, has been analyzed. The analyses include the impact of additional scatterer size, scatterer amount and their position on the performance of proposed CDFs, such as drop efficiency and quality factor (Q). For the parallel CDF, about 130 spectral Q and 99% drop efficiency can be optimally achieved at 1363 nm channel with 0.145 periodicity scatterer size, whereas for the perpendicular one, about 180 spectral Q and 99% drop efficiency can be optimally obtained at 1366 nm channel with 0.165 periodicity scatterer size. By increasing the number of scatterers, the efficiency of both configurations can be enhanced. No obvious variation is obtained by changing the scatterer position.

Keywords:

• channel drop filter
• photonic crystal
• race-track ring resonator
• integrated circuit
• FDTD

Acknowledgements

This work was supported in part by the Natural Science Foundation of Fujian Province of China under Grant Nos. F0950055 and A0910028.